Open fit canal hearing device

ABSTRACT

A hearing aid device adapted for use within the ear canal and of partially exposed in the canal types. This aid allows an air gap to substantially surround the hearing aid shell and air passages which communicate with the inner ear minimizing occlusion sensations and providing the user with an enhanced natural hearing experience. An aspect of this device is the provision of air passages in the mounting insert which securely positions the hearing aid shell in the wearer&#39;s canal. These passages are designed to stay open after insertion of the aid in the ear canal. In use, unamplified sound from the outside passes around the hearing aid shell, through the air passages in the mounting insert blending with the amplified sound emanating from the receiver. The area of air passages in the mounting insert can be tailored by the technician adapting to the hearing loss characteristics of the user.

FIELD OF THE INVENTION

This invention relates to hearing aid devices in which the entirehearing aid including microphone, receiver, circuitry and power sourceare mounted substantially within the ear canal. This invention providesbenefits to the ITE (In the ear), wherein the aid is partially exposedoutside the ear canal, the CIC (Completely in the Canal) Aid andmodifications between these types.

BACKGROUND OF THE INVENTION

A very thorough description of the Ear canal Anatomy is provided inpublished patent application Ser. No. 10/052,199 to Shennib et al theentirety of said specification is herein incorporated by reference.

Conventional hearing devices are typically characterized by the way theyfit into the individual's ear and are:

-   -   1) Behind-The-Ear (BTE) type in which the main body consisting        of the microphone, power source, amplifier and ear        phone/receiver are mounted behind the ear and the sound tube        communicating from the earphone to an ear mold which typically        fits mostly in the concha or in some instances within the ear        canal.    -   2) In-The-Ear (ITE) type fits largely in the auricle and concha        cavity areas, extending minimally into the ear canal. (These are        custom fitted)    -   3) In-The-canal (ITC) type which fits in the concha cavity and        extends into the ear canal.    -   4) Completely-In-the-Canal (CIC) type which fits completely        within the ear canal past the aperture.

Quite recently the “Open-fit” or “Over the Ear” OTE hearing aid havecome to the market which are small BTE type hearing aids with a verysmall delivery sound tube connected to a soft silicone dome or highlyvented acrylic tip that holds the tube within the ear canal. These openfit devices are designed to reduce the “occlusion effect”, which is theamplification of your own voice when your ears are blocked. Occlusioneffects are

an annoying in that a users voice sounds unnaturally highter than normalsince bone conduction becomes more pronounced as the ear canal isblocked. Teanzer et al. U.S. Pat. No. 6,009,183 and US Patentpublication 2005/0190940 to Ach-Kowalewski et al, herein incorporated byreference depict earpieces that mount entirely within the ear canal.U.S. Pat. No. 7,027,608 to Fretz et al herein incorporated by Referenceis illustrative of Open fit aids and discusses different ear tips whichcan be mounted to the sound tube of a BTE hearing aid. The tip of Fretzet al is normally open after insertion into a wearer's ear canal.

Nielsen et al, US patent publication 2005/0244026 describes a flexibleearpiece for a hearing aid. The flexible earpiece is made of sidewallswhich conforms to the wearer's ear canal and attaches to the base of theaid. While Nielsen illustrates that this earpiece connects with thesound tube of a BTE hearing aid, Nielsen do disclose that the earpiececan be used with the base from a hearing aid of the ITC type. Theearpiece of Neilson is generally closed in use as the pressure appliedto the sidewall by the wearer's ear canal will provide close contactbetween the overlapping parts of the sidewall so that no leaks occuralong the edges of the sidewall. Neilsen et al can allow some airpassage through an optional vent at the sidewall base.

US patent publication 2002/0085728 to Shennib et al is descriptive ofand extended wear CIC hearing aid wherein the body of the aid is madesmaller than a typical ear canal. This design is stated as being massproducible as these do not have to be custom fit to the wearer, as doconventional CIC aids. Shennib minimizes feedback by occluding the bonyregion with an insert preventing acoustic sound from entering the innerear.

In general, occlusion in ITC, ITE and CIC aids is somewhat mitigated bya vent tube which provides communication between the ear canal behindthe amplified sound source and the surroundings. However the presence ofvent tubes or passageways between the amplified sound source and thesurroundings leading to unwanted acoustical feedback, which must becarefully managed. Feedback is caused when amplified sound reentersmicrophone. Therefore, to limit feedback, most CIC devices the venttube, designed to opening is limited to about 0.6 to 0.8 mm diameter.

U.S. Pat. No. 4,969,534 to Kolpe et al, herein incorporated by referenceis illustrative of atypical ITC aid having a casing to which a hollowsleeve is attached which is compressed and inserted in the wears ear.The hollow sleeve allows only amplified sound from the receiver to betransmitted to the tympanic membrane.

SUMMARY OF THE INVENTION

The hearing device of the present invention pertains to devices whichare inserted substantially within the ear canal and is an improvementover conventional ITE (in the ear), ITC (in the canal) and CICcompletely in the canal aids in that it provides a natural soundingexperience with a comfortable occlusion less fit in a design whichmitigates acoustic feedback.

In the present invention a case, otherwise known as a shell, is madesmaller than conventional CIC aids, which are custom formed to conformto the wearer's ear canal. Specifically, the case of the presentinvention has a generally elliptical cross section and is of a smallercross section than that of an average wearer's ear canal when mounted inthe wearer's ear. The case of the present invention is, by design,non-conformal to the wearer's ear canal so that a gap is provided aroundthe case between the length of the case and the wearer's ear canal. Thisgap provides both a comfortable fit in that the case is in minimalcontact with the wearer's ear canal. In addition, occlusion, or ablocked sensation experienced by the majority of CIC/ITC/ITE users isvirtually eliminated. Also, the gap allows natural sounds from thesurrounding to bypass microphone and blend with the sound emanating fromthe receiver section. As the case is designed of smaller cross sectionalong the entire length of the case for most individuals, an impressionfor a conformal fitting is not necessary, making the hearing device ofthe present invention amenable to mass production.

Since the case of the present invention must be fixed within the earcanal to avoid unwanted movement of the hearing device, the case isaffixed with a flexible mounting member attached to the tip portion ofthe receiver section, which is preferably an integral part of theeasing.

The flexible mounting insert member of the present invention hasopenings to allow continued passage of natural sound from the gap formedupstream of the mounting insert to blend with amplified sound deliveredfrom the receiver section. The flexible mounting member can take on anumber of d resembling the “open fit” ear pieces conventionally used in“open fit” BTE aids. However, because of feedback issues particularlywith wearer's having significant hearing losses at higher frequencies,there is a limit to how “open” the flexible mounting member can be.

The flexible mounting insert member has apertures made by perforating orslitting or cutting custom fabricating the insert member with openings.The mounting insert member can be prefabricated with openings at thefactory or can be custom cut or the technician dispensing the aid canotherwise adjust the area manually. Alternatives include adjusting theopen area of the flexible mounting by using pre-made mounts insertshaving different opening areas or custom cutting or perforating orproviding new or additional opening to a preformed insert memberoriginally having no open area in the region between the mounting huband the outer circumference of the insert.

One embodiment of the invention shows a feature wherein rotatableadjusting members comprising vane or blades and the like are rotatedrelative to the flexible mounting member already having an open area.The adjusting member effectively blocks off more or less area and isfixed once the wearer is satisfied with the adjustment. The adjustingmember can also function to complement the mounting already provided bythe mounting member. In many instances, such as a dome or propeller typeear piece the adjusting member can be a substantial duplicate of theflexible member. The position of the adjusting member relative to themounting member can be retained by placing teeth on the mating surfacesof the adjusting and mounting members so to prevent relative movementonce secured by a screw or other fastening means.

It is remarkable that providing an open case/open fit earpiece designdoes not produce a noticeable feedback when properly adjusted. Evenwithout the use of active feedback control, it has been discovered thatproper selection or adjustment the mounting member with the appropriateopen area eliminates unwanted feedback. As the inventive design does notrequire a vent tube one explanation is that feedback is mitigated by thereturn of amplified sound to the periphery of the case which is moredistant from the microphone than from the conventional hearing aids withvent tubes. It also may be that higher frequency sounds emanated by thereceiver are redirected and absorbed at least in part by the mountingmember and also by the ear canal itself in the opportunistic gapintentionally provided by the smaller case design of the presentinvention relative to the canal. Further dampening of the returnedamplified sound can be achieved by the use of flexible elastomericmaterials as known in the art such as silicone surrounding at least inpart, the case.

Once fitted with prototype hearing aids of the present invention, witheither the propeller type or perforated dome type both without activefeedback control, long time hearing aid wearer's, including somecandidate veteran BTE customers, were exuberant over the comfort andnatural hearing experience provided with these aids.

There is logically an upper limit as to the hearing losses that can beaccommodated with this aid and are comparable with conventional CICaids.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cutaway view of a CIC type conventional Hearing aid

FIG. 2 Depicts a the general anatomy of the human ear pertaining to thefitment of CIC/ITC hearing aid device

FIG. 3 shows a conventionally mounted CIC hearing aid device in a fittedposition within the ear canal

FIG. 4 shows the aid of the present without the mounting insert.

FIG. 5 illustrates the aid of the present invention with the perforatedmounting insert.

FIG. 6 Illustrates the aid of the present invention with the perforatedmounting insert in a normally mounted position within the wearer's ear.

FIG. 7A and FIG. 7B show different views of an domed insert withopenings formed or cut into it.

FIG. 7C illustrates the use of a washer abutting the domed insert toprovide variable open area of a fixed perforated area dome insert.

FIGS. 7D and 7E shows different views of a perforated concave insertwhich open area is adjusted by means of another perforated concaveinsert which rotatably abuts the other insert allowing the effectiveopen area of the combined insert to be adjusted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the prior art CIC type hearing aid device. The case orshell 1 is shaped for insertion and conforming to the wearer's earcanal. The case 1 houses a microphone element (not shown), batterysource, amplifier circuitry that amplifies the electric voltagegenerated by the microphone element. The amplified voltage signal ispassed to a receiver element converting the amplified voltage signal toan acoustical wave which is directed through the receiver tube 3 leadingto receiver opening 4. Receiver opening 4 is directed towards thewearer's inner ear.

Faceplate 5 is mated to the case 1 providing the wearer access to thebattery compartment by way of battery door 6. Microphone opening 7 ispositioned on faceplate 1, which directs incoming surrounding sound intothe microphone element (not shown). Optional on/off volume control 8 areoften provided as well as aid removal means 9, which can be anyprotrusion to assist the wearer to remove the device for cleaning,battery replacement or adjustment.

FIG. 2 shows the overall anatomy of the ear as it relates to theplacement of CIC/ITC hearing devices. Canal aperture 20 or opening leadsto the ear canal 21 which is about 25 mm and leads to the eardrum 22.Bend area 23, which is typically referred to as the first bend ischaracteristic of most individuals and separates the bony region 24,from the cartilaginous region 25. The cartilaginous is relatively softin comparison with the bony region 24. Most CIC devices are custommolded to conform substantially to cartilaginous region 25.

FIG. 3 depicts a conventionally mounted CIC hearing aid device 30 in afitted position within the ear canal. Note that this aid conforms to theear canal forming an effective seal and reducing the conventionalproblems of direct acoustic feedback.

FIGS. 4 and 5 shows the CIC type aid of the present invention whichconsists of a case 1 which narrows towards a protrusion housing withsound tube opening 42 at the protrusion tip. The case is smaller thanconventional CIC aids in that when positioned in the wearer's ear canalfor use, an air gap is formed substantially around the case 1. At theend of the protrusion 41 is a retaining nub 43, which affixes theflexible mounting insert 51 of FIG. 5 to the case 1. It is to be alsonoted that when mounting insert 51 is mounted in the bony region of thewearer ear canal, an open area is still present in the installed insert51. These openings allow passage of surrounding acoustic waves whichenter through aperture 1 of FIG. 1 and around case 1 of FIG. 4 to blendwith the amplified sound exiting the sound tube opening 3 of FIG. 1 andbe directed towards the ear drum 22 of FIG. 2.

FIG. 6 depicts the CIC type aid of the present invention after beingmounted in a wearer's ear canal. It is readily apparent that case 1 issmaller in cross section than the wearer's ear canal along its entirelength. The average minimum gap 61 between the case at any point alongits length and the wearer's ear canal is about 0.1 mm. Again, this gapis formed substantially between the entire surface of the case and thewearer's ear canal and reduces the occlusion effect, providing thewearer with the perception of natural sounding experience. Maximumaverage gap distances between the wearer's ear canal and the case rangesfrom about 2 to about 4 mm. Larger gap sizes tend to cause unwantedfeedback even for modest acoustical gains. The cross sectional area ofcase 1 is generally elliptical and narrows along its length to the pointat which the protrusion is formed on the case. Again at the end of theprotrusion 2 is a nub 4, which retains the mounting insert 64. FIG. 6depicts the use of a perforated dome mounting insert, although apropeller type mounting insert 51 can also be used as depicted in FIGS.5. Alternatively, there are a number of alternative mounting membersthat can be affixed to the case tip 2 of FIG. 6 using a variety ofmounting means and is shown if FIGS. 7 A-E.

FIG. 6 also depicts that the mounting insert comes in substantialcontact with the bony region 62 of the ear canal generally beyond thefirst bend. This serves to stabilize the non-conformal case inside thewearer's ear canal. Additional stabilizing means which do notsubstantially interfere with the acoustical pathway provided between theinner ear, through the mounting insert and along the length of the casecan be affixed to the case as required. This can be for example flexiblemounting ribs which are affixed along the length of the case (notillustrated).

As explained earlier, openings are advantageously added to the mountinginsert, these openings allow passage of surrounding acoustic waves 63,which enter through aperture 20 and around case 1 to blend with theamplified sound exiting the sound tube opening 3 and be directed towardsthe eardrum 22 of FIG. 6.

FIGS. 7A and 7B, for example, shows a domed type insert 71 mounted andretained by nub 72 at the end of protrusion 73. The dome is providedwith slits or openings, which can be prefomed at the factory or customcut by the technician fitting the aid. For users with more pronouncedhigh frequency losses, less open areas is provided in the mountinginsert by employing by decreasing the number and/or area of theopenings. The openings can be of any shape including slits,perforations, apertures and the like and are formed in the shapedmounting insert either before or after manufacture. It is important thatin the blade or vaned type mounting inserts, the projecting vanes orblades, which emanate substantially radially from the hub portion do nottouch to the extent that openings are closed after operational placementof the case into the wearer's ear canal.

FIG. 7-C shows insertion of a washer element 75 inside the closedportion of the domed insert 71 serving to restrict air passages 74. Thedomed insert may be prefabricated at the factory. This allows the fitterto tailor the degree of occlusion by swapping out washer elements ofvarying outside diameters to effectively block more or less of airpassages 74. This design permits manufacture of just a few standardizeddome inserts with pre-made openings for adjustment with customizedoff-the-shelf washers to accommodate users with varying hearing lossesand canal shapes to optimally reduce the wearer's occlusion effect.Though not illustrated, washers can also be used in tandem with thepropeller type insert 51 (FIG. 5) or in conjunction with other insertswith fixed apertures.

FIGS. 7D and 7E show a “salt-shaker” design wherein two domed inserts 76and 77 with open areas 78 abut each other while mounted on protrusion 73in tandem. Rotation of insert 76 relative to insert 77 providesadjustable opening areas 78. Gripping ring 79 also militates againstaccidental rotation of the inserts after adjustment. During adjustment,the fitter simply rotates one insert against the other to vary theocclusion effect to consistent with the specific hearing loss andgeometry of the wearer's ear canal.

EXAMPLE 1

A wearer with moderate hearing loss was fitted with a custom moldedconventional digital type CIC hearing aid, without active feedbackcontrol and conforming to the wearer's ear canal. The aid was vented bymeans of a 0.8 mm vent tube extending near the case tip and through anopening in the faceplate. The aid was then completely inserted into thewearer's ear and retained through contact with the wearer's ear canal.The aid is adjusted to provide sufficient amplification to thesatisfaction of the wearer.

EXAMPLE 2

The same hearing aid circuit of Example 1 was placed in a smallerdiameter case, but without the conventional vent tube arrangementdescribed in Example 1. The case tip was then fitted with the propellertype insert 51 of FIG. 5. The open area of the propeller insert wasabout 50% in its unmounted state. The insert 51, was then secured in thewearer's inner ear by contact of the flexible propeller insertsubstantially within the bony region of the wearer's ear canal. Anaverage air gap of about 1 mm was formed around the case and along itslength. As the case is substantially concentrically mounted within theear canal, a substantially annular gap is formed between the case andthe ear canal. The propeller insert provided about 40% open area afterbeing mounted. The wearer commented immediately on the comfort of thefit and also commented that he could hear more naturally not hearing hisown voice when he talked. This aid provided 25% db of gain, withoutfeedback.

EXAMPLE 3

The same hearing aid circuit and case of Example 2 was then comparedusing a domed insert mounted at the case tip end. The domed insert wasfitted with openings around near central portion of the dome so thatthey would not be blocked after insertion into the wearer's ear. Theopen area was estimated at 25% after insertion of the aid into thewearer's ear. This aid provided a 30% improvement of gain with similarfavorable responses in Example 2.

EXAMPLE 4

The same hearing aid of Example 3 was fitted with a closed dome insertwith no openings in the dome. Although a 37 db gain was possible, thesame wearer although experiencing the same comfort levels of Examples 2and 3, did experience echoing and complained about hearing his own voicein comparison with the other aids tested in Examples 1, 2 and 3.

In summary, Example 4 illustrates the use of a non apertured insert In anon-conformal shell arrangement (ie case is not molded in conformancewith the wearer's ear canal) providing minimal contact with the wearer'sear canal. While this example is an improvement over example 1 in termsof comfort, Examples 2 and 3, having passageways in the insert which arenot blocked when fully inserted in its normal operating position,additionally decreases the occlusion effect, providing a more naturalhearing experience.

When fitting a wearer with moderate hearing loss, the use of an openpropeller type insert having about a 10-60% open area and morepreferably 25-50% open area after mounting has been found to provideadequate gain while significantly reducing complaints involvingocclusion.

Apertured dome inserts in general, provide less open area than propellertype inserts as there is a limit to the amount of apertures which can bemade in the dome insert before structural integrity of the insert iscompromised. Apertured dome of the present invention would have amaximum open area of about 45% in its mounted position, before the domestarts to lose its structural integrity. Improvements such as the use ofvariable wall thickness, with more thickness in the central portion ofthe dome can serve to improve the structural integrity at higher openareas. In any event, apertures or perforation are usually made towardsthe center of the domed insert as it would otherwise be blocked whenmounted in its normal operating position.

To achieve gains in excess of about 30 db gain it is preferable to usethe apertured dome type instead of the propeller type, as the dome typecan provide further restriction of air compared to the more open“propeller” type insert. Typical open areas before and after mountingare about 30 and 25% respectively.

For gains in excess of about 30 db, even smaller open areas are requiredto minimize feedback which then decreases in the feeling of opennessexperienced by the wearer.

In practice, adjustment of the open area of the insert can beaccomplished in one piece insert by selectively puncturing the insert toopen it up before the point in which feedback is noticed by the user.The disadvantage if this method is that the process must be repeated ona new insert if too much openness is provided before the wearer noticesfeedback sounds. Even with a minimal opening of 5% near In the centralportion of the otherwise closed dome insert was enough to provide thewearer's with significant hearing loss increased relief from theocclusion effect.

Alternatively, a series of pre-formed domes of with open areas rangingfrom 5% to about 60% can be utilized so that at the onset of feedback,the domed inserted is swapped out with another insert of less open area.It should be also kept in mind that each pre-formed dome be sized tocomfortably fit when mounted substantially in the wearer's Inner ear. Asthe diameter of the wearer's ear canal varies from person to person, aseries of preformed inserts of varying diameters is preferably utilized.The hole or opening pattern is made in the area generally between thehub area of the “dome” or equivalent insert to the outer periphery ofthe dome that will not come into contact with the inner ear. Any hole oropening pattern can be used, both symmetrically and non-symmetricallyplaced in the insert. Also, different sizes and shapes of openings canbe employed in combination within a specific hole pattern on the domedor equivalent insert.

Alternatively, the variable apertured design of the inventive “washer”type of FIGS. 7A, 7B or the salt shaker design of FIGS. 7C, and 7D areadvantageous in that they can be adjusted to minimize occlusioncomplaints and then backed off to decrease open area when feedbackbecomes noticeable.

In addition, the use of active feedback control as is well known in theart is advantageously incorporated into the circuitry of the aid tofurther militate against unwanted feedback sounds. U.S. Pat. No.6,097,823 to Kuo, herein incorporated by reference, is illustrative ofthe use of active feedback control in a hearing aid circuit to minimizeunwanted feedback allowing the fitter to provide a more open insert forany given hearing loss. The incorporation of active feedback control ismore advantageous when fitting wearer's with significant hearing lossesin that it does allow the use of a more open insert compared to whenactive feedback control is not utilized.

In summary, the advantages of the present invention over the prior artshould be quite apparent as it provides wearer's with relief fromocclusive sounds while providing a comfortable fit compared withconventional CIC aids. As a gap between the case and the wearer's earcanal is permissible in this particular CIC device, the use of anon-custom molded or in other words a “prefabricated” case isadvantageously employed. This allows the wearer to be fitted with aprefabricated case of standard size and shape unlike conventional CICrequiring custom molding from an impression made for the specificwearer.

Modifications to the present invention include all enhancementsconventionally applied to ITC type hearing aids including the use of waxfilters inserted in the receiver section of the aid, rechargeablebatteries, alterations of the materials of construction of the case andmounting insert, geometry of the insert etc.

1) A hearing device adapted for insertion substantially within the earcanal said device including a case containing at least a power source,and a microphone said hearing device also having a receiver elementaffixed to said case and in communication with an acoustic passagewayterminating at a tip which is directed towards the wearer's inner earwherein said case made smaller and substantially non-conformal to awearer's ear canal in its mounted position to form an open passagewaybetween the case and the ear canal along the length of said case, aflexible mounting insert attached to a tip portion of said case tosubstantially maintain said hearing device in a mounted position, saidflexible mounting insert provided with openings maintaining an open areain said mounted position, thereby creating a sound path extending fromsaid tip through said open passageway formed between the ear canal andsaid case along the length of said case, wherein an internal ventpathway extending from the vicinity of said tip to an opening in theface plate of said hearing aid is excluded. 2) The device of claim 1wherein the size of the case anywhere along its length is on average atleast 0.1 mm smaller than the size of the wearer's ear canal whenfitted. 3) The device of claim 1 wherein said openings are formed in agenerally concave insert element which is mounted on said tip portion.4) The device of claim 3 wherein said openings form a total open areafrom about 0.5% to about 35% in said insert. 5) (canceled) 6) (canceled)7) The device of claim 3 wherein the thickness of the concave insertelement increases towards the center. 8) (canceled) 9) (canceled) 10)The device of claim 1 wherein said open area is formed by a bladedelement formed of flexible blades extending substantially in a radialdirection from a hub which is mounted near said tip portion. 11) Thedevice of claim 10 wherein said open area in said insert is from about25% to about 60%. 12) (canceled) 13) The device of claim 10, whereinsaid flexible blades are curved. 14) The device of claim 1 wherein thearea of said passage is adjustable. 15) The device of claim 10 whereinat least one disc element is positioned in tandem with said bladedelement allowing adjustment of open area in said mounting insert. 16)The device of claim 1 wherein said mounting insert is provided at leastone perforation of at least 0.75 mm in diameter. 17) The device of claim1 wherein said mounting insert has a total open area from about 0.1% toabout 70%. 18) (canceled) 19) (canceled) 20) (canceled) 21) (canceled)22) The device of claim 1 wherein said mounting insert has a total openarea from about 25% to about 45%. 23) The device of claim 1, wherein thefitted cross sectional dimension of said case is on average from about0.5 mm to about 6 mm less than that of the wearer's ear canal at anycross section of said case. 24) The device of claim 1, wherein thefitted cross sectional dimension of said case is on average from about0.1 mm to about 4 mm less than that of users ear canal at any crosssection of said case. 25) (canceled) 26) The device of claim 1 whereinadditional mounting means are affixed to said case to further supportsaid hearing device within the ear canal. 27) The device of claim 26wherein said additional mounting means comprises flexible ribs attachedto the outside of the case extending along the outside of said case. 28)The device of claim 1 further comprising conventional active feedbackreduction in the amplification circuitry. 29) The device of claim 1wherein said case is prefabricated to a standard size and shape therebyavoiding custom molding to the wearer's ear canal.